Caitlyn Robertson conducted a 90-day study on a young woman named Madison to understand how working out affects mood and energy levels. She worked out with Madison three times a week, recording calories burned and how Madison felt afterward. Initially Madison reported being tired and depressed, but over the course of the study began feeling happier with more energy on non-workout days. Robertson concluded that regular exercise can transform someone who feels tired and depressed into a happier, more energetic person.